While this is strictly correct, I think the implications of what you wrote are too strong. If you move from California to another country or U.S. state, the requirements to get an "exemption" from California tax residency are essentially "convince the FTB that you have weaker ties to California than to your new location."

While arbitrary and open to abuse in theory, it appears less so in practice. Quoting from California's Guidelines For Determining [Tax] Resident Status [1], heading "Leaving California" on page 6:

> Example 4 - You and your spouse/RDP are California residents. You accept a contract to work in South America for 16 months. You lease an apartment near the job site. Your contract states that your employer will arrange your return back to California when your contract expires. Your spouse/RDP and your children will remain in California residing in the home you own.

> Determination: You maintain strong ties with California because your spouse/RDP and children remain in your California home during your absence. Your intent is to return to California, and your absence is temporary and transitory. You remain a California resident during your absence. You are taxed on income from all sources, including income earned in South America.

> Example 5 - You receive and accept a permanent job offer in Spain. You and your spouse/RDP sell your home in California, pack all of your possessions and move to Spain on May 5, 2019, with your children. You lease an apartment and enroll your children in school in Spain. You obtain a driver’s license from Spain and make numerous social connections in your new home. You have no intention of returning to California.

> Determination: You are a part-year resident. Through May 4, 2019, you were a California resident. On May 5, 2019, you became a nonresident. All your income while you were a resident is taxable by California. While you are a nonresident, only income from California sources is taxable by California.

> Example 6 - You are a resident of California. You accept a 15-month assignment in Saudi Arabia. You put your personal belongings, including your automobile, in storage in California. You have a California driver’s license and are registered to vote in California. You maintain bank accounts in California. In Saudi Arabia, you stay in a compound provided for you by your employer, and the only ties you establish there are connected to your employment. Upon completion of your assignment, you will return to California.

> Determination: You have maintained greater connections with California than you have established in Saudi Arabia. Your absence is for a temporary or transitory purpose. Therefore, you remain a California resident. As a California resident, your income from all sources is taxable by California, including the income that you earned from your assignment in Saudi Arabia.

Example 5 above is closest to what I think you were talking about by "moving from California to another country." The only way I think FTB could go after you for here is to argue that you could have an "intention" of returning to California eventually, and I do not know whether keeping your American bank accounts at California banks would be enough of a hook for FTB to decide it's worth the effort to try that argument.

For myself, if I did move from California to become an indefinite expat, I wouldn't worry too much about the FTB going after me. Opinions may vary, of course.

[1] CA FTB Publication 1031, 2019 edition: https://www.ftb.ca.gov/forms/2019/2019-1031-publication.pdf

I don't think it's a small motivation of Musk to escape the tax rate when he starts to sell his shares. Just because he vested them while in CA - if he's a resident of Texas when he sells I don't think he owes CA a dime.